public class Example3_6{
  public static void main (String args[]){
	double sum=0,item=1;
	int i=1,n=20;
	while (i<=n){
	  sum=sum+item;
	  i=i+1;
	  item=item*(1.0/i);
	}
	System.out.println("sum="+sum);
	}
}
